Primary progressive aphasia is not Alzheimer’s

Many people find it confusing to distinguish between Primary Progressive Aphasia (PPA) and Alzheimer’s, and there are good reasons for that. First, both are neurodegenerative conditions resulting from deterioration of brain tissue rather than an injury to the brain caused by stroke or head trauma. Second, the diagnosis of both conditions involves assessing language skills, deficits in which can manifest as memory problems, e.g. failure to name a common object or give the name of a familiar person. Third, some of the neurobiological abnormalities associated with Alzheimer’s, such as the accumulation of amyloid plaques in parts of the brain, have been observed also in a number of PPA patients.

PPA however is not Alzheimer’s disease. In Alzheimer’s, deterioration of language is only one component of a broad, progressive decline of mental functions that include memory and reasoning. By contrast, persons with PPA don’t have memory problems and most are able to maintain ability to take care of themselves, pursue hobbies, and, in some instances, remain employed. PPA is a disorder of language; and signs and symptoms of other clinical syndromes are not found through tests routinely used to determine the presence of other conditions.

In addition, recent research described in a previouspost showed that the toxic amyloid proteins associated with both Alzheimer’s and some PPA cases were distributed differently in people that had the PPA language dementia versus the Alzheimer’s memory dementia. Specifically, there was more amyloid in the left hemisphere parietal region of individuals with PPA compared to those with Alzheimer’s.